Description: The CFRBCS was established in 1995 to stimulate cooperative efforts to provide a resource for epidemiologic and interdisciplinary studies of individuals at high risk for breast cancer. The six participating institutions have created a powerful research infrastructure which has become a model for family studies. A series of working groups with representation from each site has standardized epidemiologic and family history survey instruments, developed uniform procedures for data collection and management, tissue collection, processing, quality control and distribution, established a mechanism of peer review for proposed studies, and adopted common language for the design and approach to informed consent. As a result, over 5,500 families with a spectrum of familial risk for breast and ovarian cancer have been recruited and 33 studies using the resources of the CFRBCS have been approved. The CFRBCS has many strengths, including its focus on the family at risk, representation from both population- and clinic-based populations, its attention to quality of data, and the broad base of expertise in breast cancer represented among the six participating sites. The CFRBCS now turns its attention to the maintenance and expansion of this resource for the purpose of carrying out an ambitious and creative research agenda which will carry the field of breast cancer research into the new millenium. The specific aims of this Core Module are: 1) to complete recruitment of families with known mutation status (either positive or negative) to support new gene discovery, gene/environment and gene/gene studies; 2) to extend minority and Ashkenazi Jewish family recruitment for gene studies and psychosocial studies; 3) to continue pathology acquisition and pathology review to support clinical/pathology studies, to expand collection of tumor blocks to include all tumor types for new gene discovery studies; 4) to continue the transformation and immortalization of lymphocytes: 5) to administer and enter follow-up questionnaires Into the database; 6) to maintain a functioning database, biospecimen repository, and distribution capability; and 7) to participate in the research modules for the competitive UO1 renewal.